GooDeal Reverse Rear Bumper Park Assist Aid Parking Sensor for GMC Chevy 20908127 New back-up sensor for Chevrolet Silverado GMC Sierra. Part #: 20908127 / 25961317. Please pay attention to the part # for fitment. Package includes: 1 piece sensor ( please buy 4 if you want a full set) Compatibility section, plaese check the description below (for reference only, it may fit a lot of more models, please check your part # before purchasing.) If you not sure, please send email to us.